Ensure that the remote control can be used with low physical effort
Some people have reduced dexterity or strength in their hands. This is a natural consequence of aging. It may also be due to degenerative conditions that restrICT movements in the joints of the fingers, hands and wrists, affect muscle power and control or cause uncontrolled movements such as shaking. Some other people have only one usable hand, due to disability, injury or simply having to hold something else in the other hand. The usable hand may be the left or the right and may not be the person’s naturally preferred hand.
Any of these conditions may make it more difficult for the person to grip objects and manipulate them with precision. Actions that require the user to press two or more buttons at the same time may be particularly difficult.
It may be difficult to hold a remote control in the correct position and press buttons without accidentally pressing other buttons at the same time. This problem is made worse if buttons are small and closely spaced because they are more difficult to accurately target and uncontrolled movements may cause the hands to stray off a button. In extreme cases, the user may accidentally strike the wrong button or strike two at the same time, causing errors. This can be particularly problematic with touchscreens or contact-sensitive controls where the user's hand can easily wander over the wrong area. Some people locate buttons by feel, so they need a way to touch buttons without activating them in order to identify them. This is of particular importance for blind people. Another source of unintended operations is buttons that repeat when they are held down for a length of time. In the UK digital switchover technical trial at Ferryside and Llansteffan, one of the issues identified with remote controls was that older users tended to hold handset buttons down too long, causing problems with menus and incorrect channel selection.
Buttons that are large, with a concave shape and well spaced will make the remote control easier for some users. In a 2004 survey of people with disabilities by Fain, large buttons and increased spacing were given very high usefulness ratings (average 3.4 and 3.3 out of a possible 4) by participants with upper mobility impairments. Concave buttons received a high rating of 2.8 out of 4. In the survey of television users carried out for these guidelines, when asked have you had any problems with the remote control?, answers included:
Buttons too small and too tight together.
Its okay but the buttons are small on the one for the TV. The one for the satellite box is better.
Guidelines survey respondents.
People may wish to hold the remote control in a position that is comfortable for their seating, reclining or standing position. When held in a position that allows users to comfortably grip and reach the buttons, the remote control may be oriented in a different direction from where they are facing, both vertically and horizontally. Some people with physical disabilities, for example, may have difficulty holding a remote control in a particular orientation so that it is pointed directly towards the equipment. In general, failure to point the remote control at the equipment was one of the issues identified in the UK digital switchover technical trial at Ferryside and Llansteffan.
Directions and techniques
Ensure that buttons are easy to press independently (high priority)
Buttons should be large and well spaced. An inactive space between buttons that is at least 50% of the button width is recommended. The On/Off button can be further ISOlated to avoid accidental activation.
Buttons can be given a concave shape to make them easier to press.
No actions should require the user to press two or more buttons at the same time.
Ensure that the remote control is easy and comfortable to use for someone with a weak grip or the use of only one hand (high priority)
The control should have an easy-grip textured surface that will not slip or turn in the hand. A matte finish tends to cause more friction than a glossy finish.
The remote control should be stable enough when placed on a flat (hard or soft) surface to be operated with one finger. One of the guidelines survey respondents described using the remote control in this way:
Not easy - I use a wheelchair and I need to balance it on the arm of it.
Guidelines survey respondent.
The remote control should be well balanced, with the weight uniformly distributed when the batteries are in place.
The size of the remote control and the stretching distances required to reach various buttons can be compared with hand size and thumb extension data such as that contained in the UK Department of Trade and industry publication Specific anthropometric and strength data for people with dexterity disability (PDF). For interactive television applications, the user may need to hold the remote control for prolonged periods, so it should not be too heavy. However, bear in mind that very small and light remote controls may also be difficult to use.
Providing a hand strap that can be attached to the control as an accessory, such as the one shown in figure 9, is a very useful choice for some people.
Avoid accidental operations (high priority)
The design of the remote control should include a way to avoid buttons being activated when they are unintentionally touched.
Let the user know that a button has been pressed (high priority)
Provide feedback in tactile, audible and/or visual form on button presses, so that the user knows when a button has been pressed, either intentionally or unintentionally.
Allow for inaccurate pointing of the control
Ensure that the remote control sends its signal across a wide angle, both horizontally and vertically, so that it is not necessary to point the remote control directly at the equipment.
Ensure that users can change the batteries
The battery compartment should be designed so that opening it and inserting or removing batteries is straightforward, within the constraints of making it safe for small children. If the battery compartment lid comes off completely, it may be easily dropped, so a hinged design may be better.
How you could test for this
Prototype designs can be compared against anthropometric data giving ranges of strength, finger size and reach for a general population. A good source is the UK Department of Trade and industry publication Specific anthropometric and strength data for people with dexterity disability. Prototypes can also be assessed against the checklist provided in the study of remote control devices for digital TV receivers published by the Department for Business Enterprise and Regulatory Reform in the UK. Industry standards for good practice such as theDigital TV Group (DTG) D-Book in the UK can also be used as checklists.
Some criteria, such as the likelihood of users making errors, are difficult to assess without user testing by a wide range of users, including older people and people with physical disabilities that result in reduced dexterity or hand control. Include tests of one-handed use, including people using their less-favoured hand.